LAS VEGAS (Reuters) - Floyd Mayweather has lived a far from perfect life but the fighter known as 'Money Man' will have the chance to cap an unprecedented boxing career on Saturday when he puts his 49-0 record on the line against Conor McGregor.

While the 40-year-old American has been a monument to perfection in the ring his pursuit of an equally accomplished life away from it ended long ago.

But it is the fighter, not the flawed man, fans will pay thousands of dollars to watch at T-Mobile Arena when Mayweather faces the crude and charismatic mixed martial arts champion for what is being hyped as the richest prize fight of all-time.

In the buildup to the bout, Mayweather rattled off a list of boxing greats who have tried and failed to beat him including Oscar De La Hoya, Manny Pacquiao and Arturo Gatti.

The police, however, have a much less flattering view of Mayweather as the boxer was accused over one 10-year stretch of assaulting five women on at least seven different occasions, including a 2010 incident resulting in a 90-day prison sentence.

Despite being at the top of Forbes list of highest paid athletes several times, Mayweather has also sparred with the United States Internal Revenue Service with reports he was forced to fight McGregor to pay off a tax debt.

During a world media tour to promote their bout McGregor, seeing an opening, mercilessly attacked Mayweather for his poor business acumen while accusing him of being uneducated and unable to read.

What Mayweather does understand is boxing and with a victory on Saturday would move ahead of former heavyweight great Rocky Marciano, who retired with a perfect 49-0 career record.

"When a fighter has lost before, if he loses again, they say, 'Oh, it's nothing, he's lost before,'" said Mayweather. "But when a fighter has been dominating for 20-some years and never lost; my legacy, my boxing record -- everything is on the line.

"Rocky Marciano did it his way, and I would just like to try to do it the Mayweather way."

Supreme confidence and self-belief are qualities that have never been in short supply for a boxer who has not tasted defeat since a controversial loss to Bulgarian Serafim Todorov in a semi-final bout at the 1996 Olympics.

That loss so stung Mayweather that he vowed never to lose again. He immediately turned professional and 21 years later has held true to his word capturing 12 world titles in five weight divisions while amassing a fortune along the way.

The money supports a lavish lifestyle that includes a Las Vegas mansion, a fleet of exotic cars and a private jet.

"My real estate portfolio is truly amazing," said Mayweather, whose businesses include a popular Las Vegas strip club where he has held 3 a.m. PT (1000 GMT) interviews in the lead-up to his showdown with McGregor. "That's a huge part of my life.

"I want my kids to do something that I wasn't able to do. I want them to be able to go college, and then the businesses that I leave for them, I want them to be able to take those businesses and take them to the next level."

The glitz of the Las Vegas Strip and a fight many pundits have denounced as nothing more than a cash grab, will mark the last stop in a decades-long journey that began 40 years ago in the grit and grime of Grand Rapids, Michigan.

Born into a boxing-obsessed family to a drug addict mother, it was there in the rust belt where Mayweather Sr., who once fought Ray Leonard, would polish and hone his son's considerable skills.

Those skills will be showcased for the final time on Saturday, Mayweather insisting he will never again step into the ring.

“This is work. This is my job," said Mayweather. "You know when your body has had enough and this is it for me.

"I gave my word already about this being my last fight. Once I gave my word to my children I knew this was it.